Celery variety ‘51-7 IPS 1’

ABSTRACT

A celery cultivar, designated 51-7 IPS 1, is disclosed, the cultivar is, for larger frame size and heavier weight, short core length, savoyed and glossy leaf color, corky root rot resistance, no fringe burn on mature leaves and also yellower heart leaf color with solid midribs. The invention relates to the seeds of celery cultivar 51-7 IPS 1, to the plants of celery cultivar 51-7 IPS land to methods for producing a celery plant by crossing the cultivar 51-7 IPS 1 with itself or another celery cultivar. The invention further relates to methods for producing a celery plant containing in its genetic material one or more transgenes and to the transgenic celery plants and plant parts produced by those methods. The invention further relates to hybrid celery seeds, plants, and plant parts produced by crossing cultivar 51-7 IPS 1 with another celery cultivar.

FIELD OF THE INVENTION

The present invention relates to a new and distinctive celery (Apium graveolens var. dulce) variety designated “51-7 IPS 1”.

BACKGROUND OF THE INVENTION

There are numerous steps in the development of any novel, desirable plant germplasm. Plant breeding begins with the analysis, definition of problems and weaknesses of the current germplasm, the establishment of program goals, and the definition of specific breeding objectives. The next step is selection of germplasm that possesses the traits to meet the program goals. The goal is to combine in a single variety or hybrid an improved combination of desirable traits from the parental germplasm. These important traits may include improved flavor, increased stalk size and weight, higher seed yield, improved color, resistance to diseases and insects, tolerance to drought and heat, and better agronomic quality.

All cultivated forms of celery belong to the species Apium graveolens var. dulce that is grown for its edible stalk. As a crop, celery is grown commercially wherever environmental conditions permit the production of an economically viable yield. In the United States, the principal growing regions are California, Florida, Arizona and Michigan. Fresh celery is available in the United States year-round, although the greatest supply is from November through January. For planting purposes, the celery season is typically divided into two seasons: summer and winter, with Florida and the southern California areas harvesting from November to July, and Michigan and northern California harvesting from July to October. Celery is consumed as fresh, raw product and as a cooked vegetable.

Celery is a cool-season biennial that grows best from 60° F. to 65° F. (16° C. to 18° C.), but will tolerate temperatures from 45° F. to 75° F. (7° C. to 24° C.). Freezing damages mature celery by splitting the petioles or causing the skin to peel, making the stalks unmarketable. This can be a problem for crops planted in the winter regions; however, celery can tolerate minor freezes early in the season.

The two main growing regions for celery in California are located along the Pacific Ocean: the central coast or summer production area (Monterey, San Benito, Santa Cruz and San Luis Obispo Counties) and the south coast or winter production area (Ventura and Santa Barbara Counties). A minor region (winter) is located in the southern deserts (Riverside and Imperial Counties).

In the south coast, celery is transplanted from early August to April for harvest from November to mid-July; in the Santa Maria area, celery is transplanted from January to August for harvest from April through December. In the central coast, fields are transplanted from March to September for harvest from late June to late December. In the southern deserts, fields are transplanted in late August for harvest in January.

Commonly used celery varieties for coastal production include Tall Utah 52-75, Conquistador and Sonora. Some shippers use their own proprietary varieties. Celery seed is very small and difficult to germinate. All commercial celery is planted as greenhouse-grown transplants. Celery grown from transplants is more uniform than from seed and takes less time to grow the crop in the field. Transplanted celery is traditionally placed in double rows on 40-inch (100-cm) beds with plants spaced between 6.0 and 7.0 inches apart.

Celery requires a relatively long and cool growing season (The physiology of vegetable crops by Pressman, CAB Intl., New York, 1997). Earlier transplanting results in a longer growing season, increased yields, and better prices. However, celery scheduled for Spring harvest often involves production in the coolest weather conditions of Winter, a period during which vernalization can occur. If adequate vernalization occurs for the variety, bolting may be initiated. Bolting is the premature rapid elongation of the main celery stem into a floral axis (i.e., during the first year for this normally biennial species). Bolting slows growth as the plant approaches marketable size leaves a stalk with no commercial value. Different varieties have different vernalization requirements, but in the presence of bolting, the length of the seed stem can be used as a means of measuring bolting tolerance that exists in each different variety. The most susceptible varieties reach their vernalization requirement earlier and have time to develop the longest seed stems, while the moderately tolerant varieties take longer to reach their vernalization requirement and have less time to develop a seed stem which would therefore be shorter. Under normal production conditions, the most tolerant varieties may not achieve their vernalization requirement and therefore not produce a measurable seed stem.

The coldest months when celery is grown in the United States are December, January and February. If celery is going to reach its vernalization requirements to cause bolting, it is generally younger celery that is exposed to this cold weather window. This celery generally matures in the months of April and May which constitutes what the celery industry calls the bolting or seeder window. The bolting or seeder window is a period where seed stems are generally going to impact the quality of the marketable celery and this is most consistently experienced in celery grown in the Southern California region. The presence of seed stems in celery can be considered a major marketable defect as set forth in the USDA grade standards. If the seed stem is longer than twice the diameter of the celery stalk or eight inches, the celery no longer meets the standards of US Grade #1. If the seed stem is longer than three times the diameter of the celery stalk, the celery is no longer marketable as US Grade #2 (United States Standards for Grades of Celery, United States Department of Agriculture, reprinted January 1997).

Celery is an allogamous biennial crop. The celery genome consists of 11 chromosomes. Its high degree of out-crossing is accomplished by insects and wind pollination. Pollinators of celery flowers include a large number of wasp, bee and fly species. Celery is subject to inbreeding depression, which appears to be dependent upon the genetic background as some lines are able to withstand selfing for three or four generations.

Celery flowers are protandrous, with pollen being released 3-6 days before stigma receptivity. At the time of stigma receptivity the stamens will have fallen and the two stigmata unfolded in an upright position. The degree of protandry varies, which makes it difficult to perform reliable hybridization, due to the possibility of accidental selfing.

Celery flowers are very small, which significantly hinders easy removal of individual anthers. Furthermore, different developmental stages of the flowers in umbels make it difficult to avoid uncontrolled pollinations. The standard hybridization technique in celery consists of selecting flower buds of the same size and eliminating the older and younger flowers. Then, the umbellets are covered with glycine paper bags for a 5-10 day period, during which the stigmas become receptive. At the time the flowers are receptive, available pollen or umbellets shedding pollen from selected male parents are rubbed on to the stigmas of the female parent.

Celery plants require a period of vernalization while in the vegetative phase in order to induce seed stalk development. A period of 6-10 weeks at 5° C. to 8° C. when the plants are greater than 4 weeks old is usually adequate. Due to a wide range of responses to the cold treatment, it is often difficult to synchronize crossing, since plants will flower at different times. However, pollen can be stored for 6-8 months at −10° C. in the presence of silica gel or calcium chloride with a viability decline of only 20-40%, thus providing flexibility to perform crosses over a longer time.

For selfing, the plant or selected umbels are caged in cloth bags. These are shaken several times during the day to promote pollen release. Houseflies (Musca domestica) can also be introduced weekly into the bags to perform pollinations.

Celery in general is an important and valuable vegetable crop. Thus, a continuing goal of celery plant breeders is to develop stable, high yielding celery cultivars that are agronomically sound to maximize the amount of yield produced on the land. To accomplish this goal, the celery breeder must select and develop celery plants that have the traits that result in superior cultivars.

The foregoing examples of the related art and limitations related therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification. The foregoing examples of the related art and limitations related therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification.

SUMMARY OF THE INVENTION

The following embodiments and aspects thereof are described in conjunction with systems, tools, and methods which are meant to be exemplary and illustrative, not limiting in scope. In various embodiments, one or more of the above-described problems have been reduced or eliminated, while other embodiments are directed to other improvements.

‘51-7 IPS 1’ is an Apium graveolens cultivar that is described as having larger frame size and heavier weight, short core length, savoyed and glossy leaf color, corky root rot resistance, no fringe burn on mature leaves and also yellower heart leaf color with solid midribs.

According to the invention, there is provided a novel celery cultivar designated 51-7 IPS 1. This invention thus relates to the seeds of celery cultivar 51-7 IPS 1, to the plants of celery cultivar 51-7 IPS 1 and to methods for producing a celery plant by crossing celery 51-7 IPS 1 with itself or another celery plant, to methods for producing a celery plant containing in its genetic material one or more transgenes and to the transgenic celery plants produced by that method. This invention also relates to methods for producing other celery cultivars derived from celery cultivar 51-7 IPS 1 and to the celery cultivar derived by the use of those methods. This invention further relates to hybrid celery seeds and plants produced by crossing celery cultivar 51-7 IPS 1 with another celery line.

In another aspect, the present invention provides regenerable cells for use in tissue culture of celery cultivar 51-7 IPS 1. The tissue culture will preferably be capable of regenerating plants having essentially all of the physiological and morphological characteristics of the foregoing celery plant, and of regenerating plants having substantially the same genotype as the foregoing celery plant. Preferably, the regenerable cells in such tissue cultures will be callus, protoplasts, meristematic cells, leaves, pollen, embryos, roots, root tips, anthers, pistils, flowers, seeds, petioles and suckers. Still further, the present invention provides celery plants regenerated from the tissue cultures of the invention.

Another aspect of the invention is to provide methods for producing other celery plants derived from celery cultivar 51-7 IPS 1. Celery cultivars derived by the use of those methods are also part of the invention.

The invention also relates to methods for producing a celery plant containing in its genetic material one or more transgenes and to the transgenic celery plant produced by those methods.

In another aspect, the present invention provides for single gene converted plants of 51-7 IPS 1. The single transferred gene may preferably be a dominant or recessive allele. Preferably, the single transferred gene will confer such traits as male sterility, herbicide resistance, insect resistance, modified fatty acid metabolism, modified carbohydrate metabolism, resistance for bacterial, fungal, or viral disease, male fertility, enhanced nutritional quality and industrial usage or the transferred gene will have no apparent value except for the purpose of being a marker for variety identification. The single gene may be a naturally occurring celery gene or a transgene introduced through genetic engineering techniques.

The invention further provides methods for developing celery plant in a celery plant breeding program using plant breeding techniques including recurrent selection, backcrossing, pedigree breeding, restriction fragment length polymorphism enhanced selection, genetic marker enhanced selection and transformation. Seeds, celery plants, and parts thereof, produced by such breeding methods are also part of the invention.

In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference by the study of the following descriptions.

DETAILED DESCRIPTION OF THE INVENTION

Definitions

In the description and tables which follow, a number of terms are used. In order to provide a clear and consistent understanding of the specification and claims, including the scope to be given such terms, the following definitions are provided:

-   Allele. An allele is any of one or more alternative form of a gene,     all of which relate to one trait or characteristic. In a diploid     cell or organism, the two alleles of a given gene occupy     corresponding loci on a pair of homologous chromosomes. -   Backcrossing. Backcrossing is a process in which a breeder     repeatedly crosses hybrid progeny back to one of the parents, for     example, a first generation hybrid F.sub.1 with one of the parental     genotype of the F.sub.1 hybrid. -   Bacterial Blight. A bacterial disease of celery caused by     Pseudomonas syringae pv. Apii. The initial symptoms appear on the     leaves as small, bright yellow, circular spots. As these enlarge     with a yellow halo, they turn to a rust color. As the spots increase     in number they merge to eventually kill the leaf tissue. Bacterial     blight is favored by cool, wet conditions and at least 10 hours of     leaf wetness is required for infection. The disease is spread by     water splashes, farm machinery and field workers especially when the     foliage is wet.

Black Streak. A physiological disorder in celery plants causing some petioles, when cut, to show “black streaks” in the lower half or throughout the entire length of the petiole, making the entire crop unmarketable. Symptoms can be triggered under field conditions by high temperatures.

Blackheart. Blackheart is due to a lack of movement of sufficient calcium that causes the plant to turn brown and begin to decay at the growing point of the plant. Celery in certain conditions, such as warm weather, grows very rapidly and is incapable of moving sufficient amounts of calcium to the growing point.

Bolting. The premature development of a flowering or seed stalk, and subsequent seed, before a plant produces a food crop. Bolting is typically caused by late planting when temperatures are low enough to cause vernalization of the plants.

Bolting Period. Also known as the bolting or seeder window, and generally occurs in celery that is transplanted from the middle of December through January and matures in April to May. The intensity and actual weeks that bolting may be observed vary from year to year, but it is generally observed in this window.

Bolting Tolerance. The amount of vernalization that is required for different celery varieties to bolt is genetically controlled. Varieties with increased tolerance to bolting require greater periods of vernalization in order to initiate bolting. A comparison of bolting tolerance between varieties can be measured by the length of the flowering or seed stem under similar vernalization conditions.

Brown Stem. A disease caused by the bacterium Pseudomonas cichorii that causes petiole necrosis. Brown Stem is characterized by a firm, brown discoloration throughout the petiole.

Celeriac or Root celery (Apium graveolens L. var. rapaceum). A plant that is related to celery but instead of having a thickened and succulent leaf petiole as in celery, celeriac has an enlarged hypocotyl and upper root that is the edible product.

Celery Heart. The center most interior petioles and leaves of the celery stalk. They are not only the smallest petioles in the stalk, but the youngest as well. Some varieties are considered heartless because they go right from very large petioles to only a couple of very small petioles. The heart is comprised of the petioles that are closest to the meristem of the celery stalk. Most straw and process type varieties have very little heart development.

Colletotrichum. One of the most common and important genera of plant-pathogenic fungi. Causes post-harvest rots, and anthracnose spots and blights of aerial plant parts. In celery it is also accompanied by curling of the foliage.

Consumable. Means material that is edible by humans.

Crackstem. The petiole can crack or split horizontally or longitudinally. Numerous cracks in several locations along the petiole are often an indication that the variety has insufficient boron nutrition. A variety's ability to utilize boron is a physiological characteristic which is genetically controlled.

Essentially all the physiological and morphological characteristics. A plant having essentially all the physiological and morphological characteristics of the recurrent parent, except for the characteristics derived from the converted gene.

Feather Leaf. Feather Leaf is a yellowing of the lower leaves and generally occurs in the outer petioles but can also be found on inner petioles of the stalk. These yellowing leaves which would normally remain in the harvested stalk are considered unacceptable. These petioles then have to be stripped off in order to meet USDA standards which effectively decreases the stalk size and yield.

Flare. The lower, generally wider portion of the petiole which is usually a paler green or white.

Fusarium Yellows. A fungal soilborne disease caused by Fusarium oxysporum f. sp. apii Race 2. Infected plants turn yellow and are stunted. Some of the large roots may have a dark brown and a water-soaked appearance. The water-conducting tissue (xylem) in the stem, crown, and root show a characteristic orange-brown discoloration.

In the later stages of infection, plants remain severely stunted and yellowed and may collapse. The disease appears most severe during warm seasons, and in heavy, wet soils.

Gene. As used herein, “gene” refers to a segment of nucleic acid. A gene can be introduced into a genome of a species, whether from a different species or from the same species, using transformation or various breeding techniques. Gross Yield (Pounds/Acre). The total yield in pounds/acre of trimmed celery plants (stalks).

Leaf Celery (Apium graveolens L. var. secalinum). A plant that has been developed primarily for leaf and seed production. Often grown in Mediterranean climates, leaf celery more closely resembles celery's wild ancestors. The stems are small and fragile and vary from solid to hollow and the leaves are fairly small and are generally bitter. This type is often used for its medicinal properties and spice.

Leaf Margin Chlorosis. A magnesium deficiency producing an interveinal chlorosis which starts at the margin of leaves.

Maturity Date. Maturity in celery can be dictated by two conditions. The first, or true maturity, is the point in time when the celery reaches maximum size distribution, but before defects such as pith, yellowing, Feather Leaf or Brown Stem appear. The second, or market maturity is an artificial maturity dictated by market conditions, i.e, the market requirement may be for 3 dozen sizes so the field is harvested at slightly below maximum yield potential because the smaller sizes are what the customers prefer at that moment.

Muck. Muck is a soil made up primarily of humus drained from swampland. It is used for growing specialty crops, such as onions, carrots, celery, and potatoes.

MUN. MUN refers to the MUNSELL Color Chart which publishes an official color chart for plant tissues according to a defined numbering system. The chart may be purchased from the Macbeth Division of Kollmorgen Instruments Corporation, 617 Little Britain Road, New Windsor, N.Y. 12553-6148.

Petiole. A petiole is the stem or limb of a leaf, the primary portion of the celery consumed.

Petiole depth. The average measurement in millimeters of the depth of the celery petiole at its narrowest point. The petiole depth measurement is taken from the outside of the petiole (which is the part of the petiole that faces the outside of the stalk) and is measured to the inside of the petiole or cup or the inner most point of the petiole that faces the center of the stalk or heart.

Petiole width. The average measurement of the width of the celery petiole in millimeters at its widest point. The measurement is taken from the side or edge of petiole to the opposite side or edge of the petiole. The measurement is taken 90 degrees from petiole depth.

Phthalides. One of the chemical compounds that are responsible for the characteristic flavor and aroma of celery.

Pith. Pith is a sponginess/hollowness/white discoloration that occurs in the petioles of celery varieties naturally as they become over-mature. In some varieties, it occurs at an earlier stage causing harvest to occur prior to ideal maturity. Pith generally occurs in the outer, older petioles first. If it occurs, these petioles are stripped off to make grade, which effectively decreases the stalk size and overall yield potential.

Plant Height. The height of the plant from the bottom of the base or butt of the celery plant to the top of the tallest leaf.

Quantitative Trait Loci. Quantitative Trait Loci (QTL) refers to genetic loci that control to some degree, numerically representable traits that are usually continuously distributed.

Regeneration. Regeneration refers to the development of a plant from tissue culture. Ribbing. The texture of the exterior surface of the celery petiole can vary from smooth to ribby depending on the variety. Ribbing is the presence of numerous ridges that run vertically along the petioles of the celery plant.

Seed Stem. A seed stem is the result of the elongation of the main stem of the celery, which is usually very compressed to almost non-existent, to form the flowering axis. The seed stem or flowering axis can reach several feet in height during full flower. The length of the seed stem is measured as the distance from the top of the basal plate (the base of the seed stem) to its terminus (the terminal growing point).

Single gene converted. Single gene converted or conversion plant refers to plants which are developed by backcrossing, or via genetic engineering, wherein essentially all of the desired morphological and physiological characteristics of a line are recovered in addition to the single gene transferred into the line via the backcrossing technique or via genetic engineering.

Stalk. A stalk is a single celery plant that is trimmed with the top or foliage and the roots removed.

Standard Stem Celery. A more traditional stem celery with moderate joint length, to be utilized and marketed as a whole stalk with 12 to 14 inch cut or for hearts in retail environment.

Stringiness. Stringiness is a physiological characteristic that is generally associated with strings that get stuck between the consumer's teeth. There are generally two sources of strings in celery. One is the vascular bundle which can be fairly elastic and behave as a string. The second is a strip of particularly strong epidermis cells called schlerenchyma which are located on the surface of the ridges of the celery varieties that have ribs.

Suckers. Suckers are auxiliary shoots that form at the base of the stalk or within the auxiliary buds between each petiole. If these shoots form between the petioles of the stalk, several petioles have to be stripped off causing the celery to become smaller and the functional yields to be decreased.

Tall Stem Celery. A stem celery with especially long petioles with primary purpose of being utilized for production of sticks or limbs.

Cultivar 51-7IPS 1

Celery 51-7 IPS 1 was created by traditional breeding originating from the publicly available lines. ‘51-7 IPS 1’ was bred and selected for larger frame size and heavier weight, short core length, savoyed and glossy leaf color, corky root rot resistance, no fringe burn on mature leaves and yellower heart leaf color with solid midribs. It is genetically uniform and stable and no genetic variants or off-types have been observed in the last generations.

A variety description of Celery Cultivar 51-7 IPS 1 is provided in Table 1.

TABLE 1 Variety Description Information Trait Plant Type 1 = Crystal Jumbo Maturity Number of Days from transplanting to 90 days in western harvest date US, (Gonzales, CA) 5 days earlier than Conquistador Class (as determined by number of days Midseason from transplanting to harvest maturity) (in western US) Plant Height 99 cm (mean) 3 cm taller than Conquistador Most Common Range  97 cm to 102 cm Height Class Tall (>61 cm) Number of Outer Petioles 9.8 0.2 more than Conquistador Number of Inner Petioles (Less than 40 cm) 3.9 per plant 0.6 more than Conquistador Stalk shape Cylindrical/compact Heart formation Full Petiole Length (mean) 31 cm 2 cm longer than Conquistador Most common range 29 cm to 33 cm Length class Tall ( > 30 cm) Width (at midpoint) 23 mm 2 mm wider than Conquistador Thickness (at midpoint between wind and  9 mm first joint) Cross Sectional Shape Slightly cupped color Dark Green ribbing moderate glossiness Moderately glossy Leaf Blade Color of Upper surface Dark green Bolting Slow bolting

The statistical analyses were performed using ANOVA. The celery variety ‘51-7 IPS 1’ is most similar to the variety Conquistador.

‘51-7 IPS 1’ is most similar to Conquistador; however ‘51-7 IPS 1’ differs in petiole color from Conquistador using Munsell color chart for plant tissue (5GY 6/10 vs. 5GY 7/8); as well as plant height (98.7 cm vs. 96.1 cm); petiole length when measured to first joint (30.5 cm vs. 28.6 cm); total number of petioles (13.8 vs. 12.9); thickness of petiole (9.2 mm vs.8.8 mm); and width of petiole (23.2 mm vs. 21.3 mm); finally, 51-7 IPS 1′ is 5 days earlier to mature than Conquistador.

This invention is also directed to methods for producing a celery plant by crossing a first parent celery plant with a second parent celery plant, wherein the first parent celery plant or second parent celery plant is the celery plant from cultivar 51-7 IPS 1. Further, both the first parent celery plant and second parent celery plant may be from cultivar 51-7 IPS 1. Therefore, any methods using celery cultivar 51-7 IPS 1 are part of this invention, such as selfing, backcrosses, hybrid breeding, and crosses to populations. Plants produced using celery cultivar 51-7 IPS 1 as at least one parent are within the scope of this invention.

In one aspect of the invention, methods for developing novel plant types are presented. In one embodiment the specific type of breeding method is pedigree selection, where both single plant selection and mass selection practices are employed. Pedigree selection, also known as the “Vilmorin system of selection,” is described in Fehr, Walter; Principles of Cultivar Development, Volume I, Macmillan Publishing Co., which is hereby incorporated by reference.

In celery breeding, lines may be selected for certain desired appropriate characteristics. To optimize crossing, it is important to note that celery is an obligate self-pollinating species. This means that the pollen is shed before stigma emergence, assuring 100% self-fertilization. Since each celery flower is an aggregate of about 10-20 individual florets (typical of the Compositae family), removal of the anther tubes containing the pollen is performed by procedures well known in the art of celery breeding.

In one embodiment, the pedigree method of breeding is practiced where selection is first practiced among F₂ plants. In the next season, the most desirable F₃ lines are first identified, and then desirable F₃ plants within each line are selected. The following season and in all subsequent generations of inbreeding, the most desirable families are identified first, then desirable lines within the selected families are chosen, and finally desirable plants within selected lines are harvested individually. A family refers to lines that were derived from plants selected from the same progeny row the preceding generation.

Using this pedigree method, two parents may be crossed using an emasculated female and a pollen donor (male) to produce F₁ offspring. To optimize crossing, it is important to note that celery is an obligate self-pollinating species. This means that the pollen is shed before stigma emergence, assuring 100% self-fertilization. Since each celery flower is an aggregate of about 10-20 individual florets, manual removal of the anther tubes containing the pollen is tedious. As such, methods of removing pollen well known to one of skill in the art, such as misting to wash the pollen off prior to fertilization, may be employed to assure crossing or hybridization. The F₁ may be self-pollinated to produce a segregating F₂ generation. Individual plants may then be selected which represent the desired phenotype in each generation (F₃, F₄, F₅, etc.) until the traits are homozygous or fixed within a breeding population.

In addition to crossing, selection may be used to identify and isolate new celery lines. In celery selection, celery seeds are planted, the plants are grown and single plant selections are made of plants with desired characteristics. Seed from the single plant selections may be harvested, separated from seeds of the other plants in the field and re-planted. The plants from the selected seed may be monitored to determine if they exhibit the desired characteristics of the originally selected line. Selection work is preferably continued over multiple generations to increase the uniformity of the new line.

Choice of breeding or selection methods depends on the mode of plant reproduction, the heritability of the trait(s) being improved, and the type of cultivar used commercially (e.g., F.sub.1 hybrid cultivar, pureline cultivar, etc.). For highly heritable traits, a choice of superior individual plants evaluated at a single location will be effective, whereas for traits with low heritability, selection should be based on mean values obtained from replicated evaluations of families of related plants. Popular selection methods commonly include pedigree selection, modified pedigree selection, mass selection, and recurrent selection.

The complexity of inheritance influences choice of the breeding method. Backcross breeding may be used to transfer one or a few favorable genes for a highly heritable trait into a desirable cultivar. This approach has been used extensively for breeding disease-resistant cultivars. Various recurrent selection techniques are used to improve quantitatively inherited traits controlled by numerous genes. The use of recurrent selection in self-pollinating crops depends on the ease of pollination, the frequency of successful hybrids from each pollination, and the number of hybrid offspring from each successful cross.

Each breeding program may include a periodic, objective evaluation of the efficiency of the breeding procedure. Evaluation criteria vary depending on the goal and objectives, but should include gain from selection per year based on comparisons to an appropriate standard, the overall value of the advanced breeding lines, and the number of successful cultivars produced per unit of input (e.g., per year, per dollar expended, etc.).

In one embodiment, promising advanced breeding lines are thoroughly tested and compared to appropriate standards in environments representative of the commercial target area(s). The best lines are candidates for new commercial cultivars; those still deficient in a few traits are used as parents to produce new populations for further selection.

These processes, which lead to the final step of marketing and distribution, usually take several years from the time the first cross or selection is made. Therefore, development of new cultivars is a time-consuming process that requires precise forward planning, efficient use of resources, and a minimum of changes in direction.

A most difficult task is the identification of individuals that are genetically superior, because for most traits the true genotypic value is masked by other confounding plant traits or environmental factors. One method of identifying a superior plant is to observe its performance relative to other experimental plants and to a widely grown standard cultivar. If a single observation is inconclusive, replicated observations provide a better estimate of its genetic worth.

The goal of celery plant breeding is to develop new, unique and superior celery cultivars. In one embodiment, the breeder initially selects and crosses two or more parental lines, followed by repeated selfing and selection, producing many new genetic combinations. The breeder can theoretically generate billions of different genetic combinations via crossing, selfing and mutations. Preferably, each year the plant breeder selects the germplasm to advance to the next generation. This germplasm may be grown under different geographical, climatic and soil conditions, and further selections are then made, during and at the end of the growing season.

In a preferred embodiment, the development of commercial celery cultivars requires the development of celery varieties, the crossing of these varieties, and the evaluation of the crosses. Pedigree breeding and recurrent selection breeding methods may be used to develop cultivars from breeding populations. Breeding programs may combine desirable traits from two or more varieties or various broad-based sources into breeding pools from which cultivars are developed by selfing and selection of desired phenotypes. The new cultivars may be crossed with other varieties and the hybrids from these crosses are evaluated to determine which have commercial potential.

Pedigree breeding is used commonly for the improvement of self-pollinating crops or inbred lines of cross-pollinating crops. Two parents which possess favorable, complementary traits are crossed to produce an F₁. An F₂ population is produced by selfing one or several F₁'s or by intercrossing two F₁'s (sib mating). Selection of the best individuals is usually begun in the F₂ population; then, beginning in the F₃, the best individuals in the best families are usually selected. Replicated testing of families, or hybrid combinations involving individuals of these families, often follows in the F₄ generation to improve the effectiveness of selection for traits with low heritability. At an advanced stage of inbreeding (e.g., F₆ and F₇), the best lines or mixtures of phenotypically similar lines are tested for potential release as new cultivars.

Mass and recurrent selections can be used to improve populations of either self- or cross-pollinating crops. A genetically variable population of heterozygous individuals may be identified or created by intercrossing several different parents. The best plants may be selected based on individual superiority, outstanding progeny, or excellent combining ability. Preferably, the selected plants are intercrossed to produce a new population in which further cycles of selection are continued.

Backcross breeding has been used to transfer genes for a simply inherited, highly heritable trait into a desirable homozygous cultivar or line that is the recurrent parent. The source of the trait to be transferred is called the donor parent. The resulting plant is expected to have the attributes of the recurrent parent (e.g., cultivar) and the desirable trait transferred from the donor parent. After the initial cross, individuals possessing the phenotype of the donor parent may be selected and repeatedly crossed (backcrossed) to the recurrent parent. The resulting plant is expected to have the attributes of the recurrent parent (e.g., cultivar) and the desirable trait transferred from the donor parent.

The single-seed descent procedure refers to planting a segregating population, harvesting a sample of one seed per plant, and using the one-seed sample to plant the next generation. When the population has been advanced from the F₂ to the desired level of inbreeding, the plants from which lines are derived will each trace to different F₂ individuals. The number of plants in a population declines each generation due to failure of some seeds to germinate or some plants to produce at least one seed. As a result, not all of the F₂ plants originally sampled in the population will be represented by a progeny when generation advance is completed.

In addition to phenotypic observations, the genotype of a plant can also be examined. There are many laboratory-based techniques available for the analysis, comparison and characterization of plant genotype; among these are Isozyme Electrophoresis, Restriction Fragment Length Polymorphisms (RFLPs), Randomly Amplified Polymorphic DNAs (RAPDs), Arbitrarily Primed Polymerase Chain Reaction (AP-PCR), DNA Amplification Fingerprinting (DAF), Sequence Characterized Amplified Regions (SCARs), Amplified Fragment Length polymorphisms (AFLPs), Simple Sequence Repeats (SSRs—which are also referred to as Microsatellites), and Single Nucleotide Polymorphisms (SNPs).

Isozyme Electrophoresis and RFLPs have been widely used to determine genetic composition. Shoemaker and Olsen, (Molecular Linkage Map of Soybean (Glycine max) p 6.131-6.138 in S. J. O'Brien (ed) Genetic Maps: Locus Maps of Complex Genomes, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y., (1993)) developed a molecular genetic linkage map that consisted of 25 linkage groups with about 365 RFLP, 11 RAPD, three classical markers and four isozyme loci. See also, Shoemaker, R. C., RFLP Map of Soybean, p 299-309, in Phillips, R. L. and Vasil, I. K., eds. DNA-Based Markers in Plants, Kluwer Academic Press, Dordrecht, the Netherlands (1994).

SSR technology is currently the most efficient and practical marker technology; more marker loci can be routinely used and more alleles per marker locus can be found using SSRs in comparison to RFLPs. For example, Diwan and Cregan described a highly polymorphic microsatellite locus in soybean with as many as 26 alleles. (Diwan, N. and Cregan, P. B., Theor. Appl. Genet. 95:22-225, 1997.) SNPs may also be used to identify the unique genetic composition of the invention and progeny varieties retaining that unique genetic composition. Various molecular marker techniques may be used in combination to enhance overall resolution.

Molecular markers, which include markers identified through the use of techniques such as Isozyme Electrophoresis, RFLPs, RAPDs, AP-PCR, DAF, SCARs, AFLPs, SSRs, and SNPs, may be used in plant breeding. One use of molecular markers is Quantitative Trait Loci (QTL) mapping. QTL mapping is the use of markers which are known to be closely linked to alleles that have measurable effects on a quantitative trait. Selection in the breeding process is based upon the accumulation of markers linked to the positive effecting alleles and/or the elimination of the markers linked to the negative effecting alleles from the plant's genome.

Molecular markers can also be used during the breeding process for the selection of qualitative traits. For example, markers closely linked to alleles or markers containing sequences within the actual alleles of interest can be used to select plants that contain the alleles of interest during a backcrossing breeding program. The markers can also be used to select toward the genome of the recurrent parent and against the markers of the donor parent. This procedure attempts to minimize the amount of genome from the donor parent that remains in the selected plants. It can also be used to reduce the number of crosses back to the recurrent parent needed in a backcrossing program. The use of molecular markers in the selection process is often called genetic marker enhanced selection or marker-assisted selection. Molecular markers may also be used to identify and exclude certain sources of germplasm as parental varieties or ancestors of a plant by providing a means of tracking genetic profiles through crosses.

Mutation breeding is another method of introducing new traits into celery varieties. Mutations that occur spontaneously or are artificially induced can be useful sources of variability for a plant breeder. The goal of artificial mutagenesis is to increase the rate of mutation for a desired characteristic. Mutation rates can be increased by many different means including temperature, long-term seed storage, tissue culture conditions, radiation (such as X-rays, Gamma rays, neutrons, Beta radiation, or ultraviolet radiation), chemical mutagens (such as base analogs like 5-bromo-uracil), antibiotics, alkylating agents (such as sulfur mustards, nitrogen mustards, epoxides, ethyleneamines, sulfates, sulfonates, sulfones, or lactones), azide, hydroxylamine, nitrous acid or acridines. Once a desired trait is observed through mutagenesis the trait may then be incorporated into existing germplasm by traditional breeding techniques. Details of mutation breeding can be found in Principles of Cultivar Development by Fehr, Macmillan Publishing Company, 1993.

The production of double haploids can also be used for the development of homozygous varieties in a breeding program. Double haploids are produced by the doubling of a set of chromosomes from a heterozygous plant to produce a completely homozygous individual. For example, see Wan et al., Theor. Appl. Genet., 77:889-892, 1989.

Descriptions of other breeding methods that are commonly used for different traits and crops can be found in one of several reference books (e.g., Principles of Plant Breeding John Wiley and Son, pp. 115-161, 1960; Allard, 1960; Simmonds, 1979; Sneep et al., 1979; Fehr, 1987; “Carrots and Related Vegetable Umbelliferae”, Rubatzky, V. E., et al., 1999).

Celery is an important and valuable vegetable crop. Thus, a continuing goal of celery plant breeders is to develop stable, high yielding celery cultivars that are agronomically sound. To accomplish this goal, the celery breeder preferably selects and develops celery plants with traits that result in superior cultivars.

This invention also is directed to methods for producing a celery cultivar plant by crossing a first parent celery plant with a second parent celery plant wherein either the first or second parent celery plant is a celery plant of the line 51-7 IPS 1. Further, both first and second parent celery plants can come from the cultivar 51-7 IPS 1. Still further, this invention also is directed to methods for producing a cultivar 51-7 IPS 1-derived celery plant by crossing cultivar 51-7 IPS 1 with a second celery plant and growing the progeny seed, and repeating the crossing and growing steps with the cultivar 51-7 IPS 1-derived plant from 0 to 7 times. Thus, any such methods using the cultivar 51-7 IPS 1 are part of this invention: selfing, backcrosses, hybrid production, crosses to populations, and the like. All plants produced using cultivar 51-7 IPS 1 as a parent are within the scope of this invention, including plants derived from cultivar 51-7 IPS 1. Advantageously, the cultivar is used in crosses with other, different, cultivars to produce first generation (F₁) celery seeds and plants with superior characteristics.

As used herein, the term plant includes plant cells, plant protoplasts, plant cell tissue cultures from which celery plants can be regenerated, plant calli, plant clumps and plant cells that are intact in plants or parts of plants, such as embryos, pollen, ovules, flowers, seeds, roots, anthers, and the like.

As is well known in the art, tissue culture of celery can be used for the in vitro regeneration of a celery plant. Tissue culture of various tissues of celery and regeneration of plants therefrom is well known and widely published. For example, reference may be had to Teng et al., HortScience. 1992, 27: 9, 1030-1032 Teng et al., HortScience. 1993, 28: 6, 669-1671, Zhang et al., Journal of Genetics and Breeding. 1992, 46: 3, 287-290, Webb et al., Plant Cell Tissue and Organ Culture. 1994, 38: 1, 77-79, Curtis et al., Journal of Experimental Botany. 1994, 45: 279, 1441-1449, Nagata et al., Journal for the American Society for Horticultural Science. 2000, 125: 6, 669-672. It is clear from the literature that the state of the art is such that these methods of obtaining plants are, and were, “conventional” in the sense that they are routinely used and have a very high rate of success. Thus, another aspect of this invention is to provide cells which upon growth and differentiation produce celery plants having the physiological and morphological characteristics of variety 51-7 IPS 1.

With the advent of molecular biological techniques that have allowed the isolation and characterization of genes that encode specific protein products, scientists in the field of plant biology developed a strong interest in engineering the genome of plants to contain and express foreign genes, or additional, or modified versions of native, or endogenous, genes (perhaps driven by different promoters) in order to alter the traits of a plant in a specific manner. Such foreign additional and/or modified genes are referred to herein collectively as transgenes. Over the last fifteen to twenty years several methods for producing transgenic plants have been developed, and the present invention, in particular embodiments, also relates to transformed versions of the claimed line.

Plant transformation preferably involves the construction of an expression vector that will function in plant cells. Such a vector may comprise DNA comprising a gene under control of or operatively linked to a regulatory element (for example, a promoter). The expression vector may contain one or more such operably linked gene/regulatory element combinations. The vector(s) may be in the form of a plasmid, and can be used alone or in combination with other plasmids, to provide transformed celery plants, using transformation methods as described below to incorporate transgenes into the genetic material of the celery plant(s).

Expression Vectors for Celery Transformation

Marker Genes

Expression vectors include at least one genetic marker, operably linked to a regulatory element (a promoter, for example) that allows transformed cells containing the marker to be either recovered by negative selection, i.e., inhibiting growth of cells that do not contain the selectable marker gene, or by positive selection, i.e., screening for the product encoded by the genetic marker. Many commonly used selectable marker genes for plant transformation are well known in the transformation arts, and include, for example, genes that code for enzymes that metabolically detoxify a selective chemical agent which may be an antibiotic or a herbicide, or genes that encode an altered target which is insensitive to the inhibitor. A few positive selection methods are also known in the art.

One commonly used selectable marker gene for plant transformation is the neomycin phosphotransferase II (nptII) gene, isolated from transposon Tn5, which when placed under the control of plant regulatory signals confers resistance to kanamycin. Fraley et al., Proc. Natl. Acad. Sci. U.S.A., 80:4803 (1983). Another commonly used selectable marker gene is the hygromycin phosphotransferase gene which confers resistance to the antibiotic hygromycin. Vanden Elzen et al., Plant Mol. Biol., 5:299 (1985).

Additional selectable marker genes of bacterial origin that confer resistance to antibiotics include gentamycin acetyl transferase, streptomycin phosphotransferase, aminoglycoside-3′-adenyl transferase, the bleomycin resistance determinant. Hayford et al., Plant Physiol. 86:1216 (1988), Jones et al., Mol. Gen. Genet., 210:86 (1987), Svab et al., Plant Mol. Biol. 14:197 (1990<Hille et al., Plant Mol. Biol. 7:171 (1986). Other selectable marker genes confer resistance to herbicides such as glyphosate, glufosinate or broxynil. Comai et al., Nature 317:741-744 (1985), Gordon-Kamm et al., Plant Cell 2:603-618 (1990) and Stalker et al., Science 242:419-423 (1988).

Other selectable marker genes for plant transformation are not of bacterial origin. These genes include, for example, mouse dihydrofolate reductase, plant 5-enolpyruvylshikimate-3-phosphate synthase and plant acetolactate synthase. Eichholtz et al., Somatic Cell Mol. Genet. 13:67 (1987), Shah et al., Science 233:478 (1986), Charest et al., Plant Cell Rep. 8:643 (1990).

Another class of marker genes for plant transformation requires screening of presumptively transformed plant cells rather than direct genetic selection of transformed cells for resistance to a toxic substance such as an antibiotic. These genes are particularly useful to quantify or visualize the spatial pattern of expression of a gene in specific tissues and are frequently referred to as reporter genes because they can be fused to a gene or gene regulatory sequence for the investigation of gene expression. Commonly used genes for screening presumptively transformed cells include β-glucuronidase (GUS), β-galaetesidase, luciferase and chloramphenicol, acetyltransferase. Jefferson, R. A., Plant Mol. Biol. Rep. 5:387 (1987), Teeri et al., EMBO J. 8:343 (1989), Koncz et al., Proc. Natl. Acad. Sci U.S.A. 84:131 (1987), DeBlock et al., EMBO J. 3:1681 (1984).

Recently, in vivo methods for visualizing GUS activity that do not require destruction of plant tissue have been made available. Molecular Probes publication 2908, Imagene Green™, p. 1-4 (1993) and Naleway et al., J. Cell Biol. 115:151a (1991). However, these in vivo methods for visualizing GUS activity have not proven useful for recovery of transformed cells because of low sensitivity, high fluorescent backgrounds and limitations associated with the use of luciferase genes as selectable markers.

More recently, a gene encoding Green Fluorescent Protein (GFP) has been utilized as a marker for gene expression in prokaryotic and eukaryotic cells. Chalfie et al., Science 263:802 (1994). GFP and mutants of GFP may be used as screenable markers.

Promoters

Genes included in expression vectors preferably are driven by nucleotide sequence comprising a regulatory element, for example, a promoter. Several types of promoters are now well known in the transformation arts, as are other regulatory elements that can be used alone or in combination with promoters.

As used herein, promoter includes reference to a region of DNA upstream from the start of transcription and involved in recognition and binding of RNA polymerase and other proteins to initiate transcription. A “plant promoter” is a promoter capable of initiating transcription in plant cells. Examples of promoters under developmental control include promoters that preferentially initiate transcription in certain tissues, such as leaves, roots, seeds, fibers, xylem vessels, tracheids, or sclerenchyma. Such promoters are referred to as “tissue-preferred”. Promoters which initiate transcription only in certain tissue are referred to as “tissue-specific”. A “cell type” specific promoter primarily drives expression in certain cell types in one or more organs, for example, vascular cells in roots or leaves. An “inducible” promoter is a promoter which is under environmental control. Examples of environmental conditions that may affect transcription by inducible promoters include anaerobic conditions or the presence of light. Tissue-specific, tissue-preferred, cell type specific, and inducible promoters constitute the class of “non-constitutive” promoters. A “constitutive promoter” is a promoter which is active under most environmental conditions.

A. Inducible Promoters

An inducible promoter is operably linked to a gene for expression in celery. Optionally, the inducible promoter is operably linked to a nucleotide sequence encoding a signal sequence which is operably linked to a gene for expression in celery. With an inducible promoter the rate of transcription increases in response to an inducing agent.

Any inducible promoter can be used in the instant invention. See Ward et al., Plant Mol. Biol. 22:361-366 (1993). Exemplary inducible promoters include, but are not limited to, that from the ACEI system which responds to copper (Meft et al., PNAS 90:4567-4571 (1993)); In2 gene from maize which responds to benzenesulfonamide herbicide safeners (Hershey et al., Mol. Gen Genetics 227:229-237 (1991) and Gatz et al., Mol. Gen. Genetics 243:32-38 (1994)) or Tet repressor from Tn10 (Gatz et al., Mol. Gen. Genetics 227:229-237 (1991). A particularly preferred inducible promoter is a promoter that responds to an inducing agent to which plants do not normally respond. An exemplary inducible promoter is the inducible promoter from a steroid hormone gene, the transcriptional activity of which is induced by a glucocorticosteroid hormone. Schena et al., Proc. Natl. Acad. Sci. U.S.A. 88:0421 (1991).

B. Constitutive Promoters

A constitutive promoter may be operably linked to a gene for expression in celery or the constitutive promoter may operably linked to a nucleotide sequence encoding a signal sequence which is operably linked to a gene for expression in celery.

Many different constitutive promoters can be utilized in the instant invention. Exemplary constitutive promoters include, but are not limited to, the promoters from plant viruses such as the 35S promoter from CaMV (Odell et al., Nature 313:810-812 (1985) and the promoters from such genes as rice actin (McElroy et al., Plant Cell 2:163-171 (1990)); ubiquitin (Christensen et al., Plant Mol. Biol. 12:619-632 (1989) and Christensen et al., Plant Mol. Biol. 18:675-689 (1992)); pEMU (Last et al., Theor. Appl. Genet. 81:581-588 (1991)); MAS (Velten et al., EMBO J. 3:2723-2730 (1984)) and maize H3 histone (Lepetit et al., Mol. Gen. Genetics 231:276-285 (1992) and Atanassova et al., Plant Journal 2 (3): 291-300 (1992)). The ALS promoter, Xbal/Ncol fragment 5′ to the Brassica napus ALS3 structural gene (or a nucleotide sequence similarity to said Xbal/Ncol fragment), represents a particularly useful constitutive promoter. See PCT application WO96/30530.

C. Tissue-Specific or Tissue-Preferred Promoters

A tissue-specific promoter may be operably linked to a gene for expression in celery. Optionally, the tissue-specific promoter is operably linked to a nucleotide sequence encoding a signal sequence which is operably linked to a gene for expression in celery. Plants transformed with a gene of interest operably linked to a tissue-specific promoter produce the protein product of the transgene exclusively, or preferentially, in a specific tissue.

Any tissue-specific or tissue-preferred promoter can be utilized in the instant invention. Exemplary tissue-specific or tissue-preferred promoters include, but are not limited to, a root-preferred promoter, such as that from the phaseolin gene (Murai et al., Science 23:476-482 (1983) and Sengupta-Gopalan et al., Proc. Natl. Acad. Sci. U.S.A. 82:3320-3324 (1985)); a leaf-specific and light-induced promoter such as that from cab or rubisco (Simpson et al., EMBO J. 4(11):2723-2729 (1985) and Timko et al., Nature 318:579-582 (1985)); an anther-specific promoter such as that from LAT52 (Twell et al., Mol. Gen. Genetics 217:240-245 (1989)); a pollen-specific promoter such as that from Zm13 (Guerrero et al., Mol. Gen. Genetics 244:161-168 (1993)) or a microspore-preferred promoter such as that from apg (Twell et al., Sex. Plant Reprod. 6:217-224 (1993).

Signal Sequences for Targeting Proteins to Subcellular Compartments

Transport of protein produced by transgenes to a subcellular compartment such as the chloroplast, vacuole, peroxisome, glyoxysome, cell wall or mitochondroin or for secretion into the apoplast, is accomplished by means of operably linking the nucleotide sequence encoding a signal sequence to the 5′ and/or 3′ region of a gene encoding the protein of interest. Targeting sequences at the 5′ and/or 3′ end of the structural gene may determine, during protein synthesis and processing, where the encoded protein is ultimately compartmentalized.

The presence of a signal sequence directs a polypeptide to either an intracellular organelle or subcellular compartment or for secretion to the apoplast. Many signal sequences are known in the art. See, for example Becker et al., Plant Mol. Biol. 20:49 (1992), Close, P. S., Master's Thesis, Iowa State University (1993), Knox, C., et al., Structure and Organization of Two Divergent Alpha-Amylase Genes from Barley, Plant Mol. Biol. 9:3-17 (1987), Lerner et al., Plant Physiol. 91:124-129 (1989), Fontes et al., Plant Cell 3:483-496 (1991), Matsuoka et al., Proc. Natl. Acad. Sci. 88:834 (1991), Gould et al., J. Cell. Biol. 108:1657 (1989), Creissen et al., Plant J. 2:129 (1991), Kalderon, et al., A short amino acid sequence able to specify nuclear location, Cell 39:499-509 (1984), Steifel, et al., Expression of a maize cell wall hydroxyproline-rich glycoprotein gene in early leaf and root vascular differentiation, Plant Cell 2:785-793 (1990).

Foreign Protein Genes and Agronomic Genes

With transgenic plants according to the present invention, a foreign protein can be produced in commercial quantities. Thus, techniques for the selection and propagation of transformed plants, which are well understood in the art, yield a plurality of transgenic plants that are harvested in a conventional manner, and a foreign protein then can be extracted from a tissue of interest or from total biomass. Protein extraction from plant biomass can be accomplished by known methods which are discussed, for example, by Heney and Orr, Anal. Biochem. 114:92-6 (1981).

According to a preferred embodiment, the transgenic plant provided for commercial production of foreign protein is celery. In another preferred embodiment, the biomass of interest is seed. For transgenic plants that show higher levels of expression, a genetic map can be generated, primarily via conventional RFLP, PCR and SSR analysis, which identifies the approximate chromosomal location of the integrated DNA molecule. For exemplary methodologies in this regard, see Glick and Thompson, Methods in Plant Molecular Biology and Biotechnology CRC Press, Boca Raton 269:284 (1993). Map information concerning chromosomal location is useful for proprietary protection of a subject transgenic plant. If unauthorized propagation is undertaken and crosses made with other germplasm, the map of the integration region can be compared to similar maps for suspect plants, to determine if the latter have a common parentage with the subject plant. Map comparisons may involve hybridizations, RFLP, PCR, SSR and sequencing, all of which are conventional techniques.

Likewise, by means of the present invention, agronomic genes can be expressed in transformed plants. More particularly, plants can be genetically engineered to express various phenotypes of agronomic interest. Exemplary genes implicated in this regard include, but are not limited to, those categorized below:

1. Genes That Confer Resistance to Pests or Disease and that Encode:

-   A. Plant disease resistance genes. Plant defenses are often     activated by specific interaction between the product of a disease     resistance gene (R) in the plant and the product of a corresponding     avirulence (Avr) gene in the pathogen. A plant line can be     transformed with cloned resistance gene to engineer plants that are     resistant to specific pathogen strains. See, for example Jones et     al., Science 266:789 (1994) (cloning of the tomato Cf-9 gene for     resistance to Cladosporium fulvum); Martin et al., Science     262:1432 (1993) (tomato Pto gene for resistance to Pseudomonas     syringae pv. Tomato encodes a protein kinase); Mindrinos et al.,     Cell 78:1089 (1994) (Arabidopsis RSP2 gene for resistance to     Pseudomonas syringae). -   B. A Bacillus thuringiensis protein, a derivative thereof or a     synthetic polypeptide modeled thereon. See, for example, Geiser et     al., Gene 48:109 (1986), who disclose the cloning and nucleotide     sequence of a Bt δ-endotoxin gene. Moreover, DNA molecules encoding     δ-endotoxin genes can be purchased from American Type Culture     Collection, Manassas, Va., for example, under ATCC Accession Nos.     40098, 67136, 31995 and 31998. -   C. A lectin. See, for example, the disclose by Van Damme et al.,     Plant Molec. Biol. 24:25 (1994), who disclose the nucleotide     sequences of several Clivia miniata mannose-binding lectin genes. -   D. A vitamin-binding protein such as avidin. See PCT application     US93/06487, the contents of which are hereby incorporated by     reference. The application teaches the use of avidin and avidin     homologues as larvicides against insect pests. -   E. An enzyme inhibitor, for example, a protease or proteinase     inhibitor or an amylase inhibitor. See, for example, Abe et al., J.     Biol. Chem. 262:16793 (1987) (nucleotide sequence of rice cysteine     proteinase inhibitor), Huub et al., Plant Molec. Biol. 21:985 (1993)     (nucleotide sequence of cDNA encoding tobacco proteinase inhibitor     I), Sumitani et al., Biosci. Biotoch. Biochem. 57:1243 (1993)     (nucleotide sequence of Streptomyces nitrosporeus alpha.-amylase     inhibitor). -   F. An insect-specific hormone or pheromone such as an ecdysteroid     and juvenile hormone, a variant thereof, a mimetic based thereon, or     an antagonist or agonist thereof. See, for example, the disclosure     by Hammock et al., Nature 344:458 (1990), of baculovirus expression     of cloned juvenile hormone esterase, an inactivator of juvenile     hormone. -   G. An insect-specific peptide or neuropeptide which, upon     expression, disrupts the physiology of the affected pest. For     example, see the disclosures of Regan, J. Biol. Chem. 269:9 (1994)     (expression cloning yields DNA coding for insect diuretic hormone     receptor), and Pratt et al., Biochem. Biophys. Res. Comm.     163:1243 (1989) (an allostatin is identified in Diploptera puntata).     See also U.S. Pat. No. 5,266,317 to Tomalski et al., who disclose     genes encoding insect-specific, paralytic neurotoxins. -   H. An insect-specific venom produced in nature by a snake, a wasp,     etc. For example, see Pang et al., Gene 116:165 (1992), for     disclosure of heterologous expression in plants of a gene coding for     a scorpion insectotoxic peptide. -   I. An enzyme responsible for a hyper accumulation of a monterpene, a     sesquiterpene, a steroid, hydroxamic acid, a phenylpropanoid     derivative or another non-protein molecule with insecticidal     activity. -   J. An enzyme involved in the modification, including the     post-translational modification, of a biologically active molecule;     for example, a glycolytic enzyme, a proteolytic enzyme, a lipolytic     enzyme, a nuclease, a cyclase, a transaminase, an esterase, a     hydrolase, a phosphatase, a kinase, a phosphorylase, a polymerase,     an elastase, a chitinase and a glucanase, whether natural or     synthetic. See PCT application WO 93/02197 in the name of Scott et     al., which discloses the nucleotide sequence of a callase gene. DNA     molecules which contain chitinase-encoding sequences can be     obtained, for example, from the ATCC under Accession Nos. 39637     and 67152. See also Kramer et al., Insect Biochem. Molec. Biol.     23:691 (1993), who teach the nucleotide sequence of a cDNA encoding     tobacco hookworm chitinase, and Kawalleck et al., Plant Molec. Biol.     21:673 (1993), who provide the nucleotide sequence of the parsley     ubi4-2 polyubiquitin gene. -   K. A molecule that stimulates signal transduction. For example, see     the disclosure by Botella et al., Plant Molec. Biol. 24:757 (1994),     of nucleotide sequences for mung celery calmodulin cDNA clones, and     Griess et al., Plant Physiol. 104:1467 (1994), who provide the     nucleotide sequence of a maize calmodulin cDNA clone. -   L. A hydrophobic moment peptide. See PCT application WO95/16776     (disclosure of peptide derivatives of tachyolesin which inhibit     fungal plant pathogens) and PCT application WO95/18855 (teaches     synthetic antimicrobial peptides that confer disease resistance),     the respective contents of which are hereby incorporated by     reference. -   M. A membrane permease, a channel former or a channel blocker. For     example, see the disclosure of Jaynes et al., Plant Sci 89:43     (1993), of heterologous expression of a cecropin-β, lytic peptide     analog to render transgenic tobacco plants resistant to Pseudomonas     solanacearum. -   N. A viral-invasive protein or a complex toxin derived therefrom.     For example, the accumulation of viral coat proteins in transformed     plant cells imparts resistance to viral infection and/or disease     development effected by the virus from which the coat protein gene     is derived, as well as by related viruses. See Beachy et al., Ann.     rev. Phytopathol. 28:451 (1990). Coat protein-mediated resistance     has been conferred upon transformed plants against alfalfa mosaic     virus, cucumber mosaic virus, tobacco streak virus, potato virus X,     potato virus Y, tobacco etch virus, tobacco rattle virus and tobacco     mosaic virus. Id. -   O. An insect-specific antibody or an immunotoxin derived therefrom.     Thus, an antibody targeted to a critical metabolic function in the     insect gut would inactivate an affected enzyme, killing the insect.     Cf. Taylor et al., Abstract #497, Seventh Int'l Symposium on     Molecular Plant-Microbe Interactions (Edinburgh, Scotland) (1994)     (enzymatic inactivation in transgenic tobacco via production of     single-chain antibody fragments). -   P. A virus-specific antibody. See, for example, Tavladoraki et al.,     Nature 366:469 (1993), who show that transgenic plants expressing     recombinant antibody genes are protected from virus attack. -   Q. A developmental-arrestive protein produced in nature by a     pathogen or a parasite. Thus, fungal endo-α-1,4-D-polygalacturonases     facilitate fungal colonization and plant nutrient release by     solubilizing plant cell wall homo-α-1,4-D-galacturonase. See Lamb at     al., Bio/Technology 10:1436 (1992). The cloning and characterization     of a gene which encodes a celery endopolygalacturonase-inhibiting     protein is described by Toubart et al., Plant J. 2:367 (1992). -   R. A development-arrestive protein produced in nature by a plant.     For example, Logemann et al., Biol/Technology 10:305 (1992), have     shown that transgenic plants expressing the barley     ribosome-inactivating gene have an increased resistance to fungal     disease. -   S. A celery mosaic potyvirus (LMV) coat protein gene introduced into     Lactuca sativa in order to increase its resistance to LMV infection.     See Dinant et al., Molecular Breeding. 1997, 3: 1, 75-86.     2. Genes that Confer Resistance to an Herbicide, for Example: -   A. A herbicide that inhibits the growing point or meristem, such as     an imidazalinone or a sulfonylurea. Exemplary genes in this category     code for mutant ALS and AHAS enzyme as described, for example, by     Lee et al., EMBO J. 7:1241 (1988), and Miki et al., Theor. Appl.     Genet. 80:449 (1990), respectively. -   B. Glyphosate (resistance impaired by mutant     5-enolpyruvl-3-phosphikimate synthase (EPSP) and aroA genes,     respectively) and other phosphono compounds such as glufosinate     (phosphinothricin acetyl transferase, PAT and Streptomyces     hygroscopicus phosphinothricin-acetyl transferase PAT bar genes),     and pyridinoxy or phenoxy propionic acids and cycloshexones (ACCase     inhibitor-encoding genes). See, for example, U.S. Pat. No. 4,940,835     to Shah, et al., which discloses the nucleotide sequence of a form     of EPSP which can confer glyphosate resistance. A DNA molecule     encoding a mutant aroA gene can be obtained under ATCC accession     number 39256, and the nucleotide sequence of the mutant gene is     disclosed in U.S. Pat. No. 4,769,061 to Comai. See also     Umaballava-Mobapathie in Transgenic Research. 1999, 8: 1, 33-44 that     discloses Lactuca sativa resistant to glufosinate. European patent     application No. 0 333 033 to Kumada at al., and U.S. Pat. No.     4,975,374 to Goodman et al., disclose nucleotide sequences of     glutamine synthetase genes which confer resistance to herbicides     such as L-phosphinothricin. The nucleotide sequence of a     phosphinothricin-acetyl-transferase gene is provided in European     application No. 0 242 246 to Leemans et al., DeGreef et al.,     Bio/Technology 7:61 (1989), describe the production of transgenic     plants that express chimeric bar genes coding for phosphinothricin     acetyl transferase activity. Exemplary of genes conferring     resistance to phenoxy propionic acids and cycloshexones, such as     sethoxydim and haloxyfop are the Accl-S1, Accl-S2 and Accl-S3 genes     described by Marshall et al., Theor. Appl. Genet. 83:435 (1992). -   C. A herbicide that inhibits photosynthesis, such as a triazine     (psbA and gs+ genes) and a benzonitrile (nitrilase gene). Przibilla     et al., Plant Cell 3:169 (1991), describe the transformation of     Chlamydomonas with plasmids encoding mutant psbA genes. Nucleotide     sequences for nitrilase genes are disclosed in U.S. Pat. No.     4,810,648 to Stalker, and DNA molecules containing these genes are     available under ATCC Accession Nos. 53435, 67441, and 67442. Cloning     and expression of DNA coding for a glutathione S-transferase is     described by Hayes et al., Biochem. J. 285:173 (1992). -   D. Acetohydroxy acid synthase, which has been found to make plants     that express this enzyme resistant to multiple types of herbicides,     has been introduced into a variety of plants. See Hattori et al.,     Mol. Gen. Genet. 246:419, 1995. Other genes that confer tolerance to     herbicides include a gene encoding a chimeric protein of rat     cytochrome P4507A1 and yeast NADPH-cytochrome P450 oxidoreductase     (Shiota et al., Plant Physiol., 106:17, 1994), genes for glutathione     reductase and superoxide dismutase (Aono et al., Plant Cell Physiol.     36:1687, 1995), and genes for various phosphotransferases (Datta et     al., Plant Mol. Biol. 20:619, 1992). -   E. Protoporphyrinogen oxidase (protox) is necessary for the     production of chlorophyll, which is necessary for all plant     survival. The protox enzyme serves as the target for a variety of     herbicidal compounds. These herbicides also inhibit growth of all     the different species of plants present, causing their total     destruction. The development of plants containing altered protox     activity which are resistant to these herbicides are described in     U.S. Pat. Nos. 6,288,306; 6,282,837; 5,767,373; and international     publication WO 01/12825.     3. Genes that Confer or Contribute to a Value-Added Trait, such as: -   A. Increased iron content of the celery, for example by transforming     a plant with a soybean ferritin gene as described in Goto et al.,     Acta Horticulturae. 2000, 521, 101-109. -   B. Decreased nitrate content of leaves, for example by transforming     a celery with a gene coding for a nitrate reductase. See for example     Curtis et al., Plant Cell Report. 1999, 18: 11, 889-896. -   C. Increased sweetness of the celery by transferring a gene coding     for monellin that elicits a flavor sweeter than sugar on a molar     basis. See Penarrubia et al., Biotechnology. 1992, 10: 5, 561-564. -   D. Modified fatty acid metabolism, for example, by transforming a     plant with an antisense gene of stearyl-ACP desaturase to increase     stearic acid content of the plant. See Knultzon et al., Proc. Natl.     Acad. Sci. USA 89:2625 (1992). -   E. Modified carbohydrate composition effected, for example, by     transforming plants with a gene coding for an enzyme that alters the     branching pattern of starch. See Shiroza et al., J. Bacteriol.     170:810 (1988) (nucleotide sequence of Streptococcus mutants     fructosyltransferase gene), Steinmetz et al., Mol. Gen. Genet.     20:220 (1985) (nucleotide sequence of Bacillus subtilis levansucrase     gene), Pen et al., Bio/Technology 10:292 (1992) (production of     transgenic plants that express Bacillus licheniformis α-amylase),     Elliot et al., Plant Molec. Biol. 21:515 (1993) (nucleotide     sequences of tomato invertase genes), Sogaard et al., J. Biol. Chem.     268:22480 (1993) (site-directed mutagenesis of barley α-amylase     gene), and Fisher et al., Plant Physiol. 102:1045 (1993) (maize     endosperm starch branching enzyme II).     4. Genes that Control Male-Sterility -   A. Introduction of a deacetylase gene under the control of a     tapetum-specific promoter and with the application of the chemical     N-Ac-PPT. See international publication WO 01/29237. -   B. Introduction of various stamen-specific promoters. See     international publications WO 92/13956 and WO 92/13957. -   C. Introduction of the barnase and the barstar genes. See Paul et     al., Plant Mol. Biol. 19:611-622, 1992).     Methods for Celery Transformation

Numerous methods for plant transformation have been developed, including biological and physical, plant transformation protocols. See, for example, Miki et al., “Procedures for Introducing Foreign DNA into Plants” in Methods in Plant Molecular Biology and Biotechnology, Glick B. R. and Thompson, J. E. Eds. (CRC Press, Inc., Boca Raton, 1993) pages 67-88. In addition, expression vectors and in vitro culture methods for plant cell or tissue transformation and regeneration of plants are available. See, for example, Gruber et al., “Vectors for Plant Transformation” in Methods in Plant Molecular Biology and Biotechnology, Glick B. R. and Thompson, J. E. Eds. (CRC Press, Inc., Boca Raton, 1993) pages 89-119.

A. Agrobacterium-Mediated Transformation

One method for introducing an expression vector into plants is based on the natural transformation system of Agrobacterium. See, for example, Horsch et al., Science 227:1229 (1985). Curtis et al., Journal of Experimental Botany. 1994, 45: 279, 1441-1449, Torres et al., Plant cell Tissue and Organic Culture. 1993, 34: 3, 279-285, Dinant et al., Molecular Breeding. 1997, 3: 1, 75-86. A. tumefaciens and A. rhizogenes are plant pathogenic soil bacteria which genetically transform plant cells. The Ti and Ri plasmids of A. tumefaciens and A. rhizogenes, respectively, carry genes responsible for genetic transformation of the plant. See, for example, Kado, C. I., Crit. Rev. Plant Sci. 10:1 (1991). Descriptions of Agrobacterium vector systems and methods for Agrobacterium-mediated gene transfer are provided by Gruber et al., supra, Miki et al., supra, and Moloney et al., Plant Cell Reports 8:238 (1989). See also, U.S. Pat. No. 5,591,616 issued Jan. 7, 1997.

B. Direct Gene Transfer

Several methods of plant transformation collectively referred to as direct gene transfer have been developed as an alternative to Agrobacterium-mediated transformation. A generally applicable method of plant transformation is microprojectile-mediated transformation wherein DNA is carried on the surface of microprojectiles measuring 1 to 4 μm. The expression vector is introduced into plant tissues with a biolistic device that accelerates the microprojectiles to speeds of 300 to 600 m/s which is sufficient to penetrate plant cell walls and membranes. Russell, D. R., et al. Pl. Cell. Rep. 12(3, January), 165-169 (1993), Aragao, F. J. L., et al. Plant Mol. Biol. 20(2, October), 357-359 (1992), Aragao, F. J. L., et al. Pl. Cell. Rep. 12(9, July), 483-490 (1993). Aragao, Theor. Appl. Genet. 93: 142-150 (1996), Kim, J.; Minamikawa, T. Plant Science 117: 131-138 (1996), Sanford et al., Part. Sci. Technol. 5:27 (1987), Sanford, J. C., Trends Biotech. 6:299 (1988), Klein et al., Bio/Technology 6:559-563 (1988), Sanford, J. C., Physiol Plant 7:206 (1990), Klein et al., Biotechnology 10:268 (1992).

Another method for physical delivery of DNA to plants is sonication of target cells. Zhang et al., Bio/Technology 9:996 (1991). Alternatively, liposome or spheroplast fusion has been used to introduce expression vectors into plants. Deshayes et al., EMBO J., 4:2731 (1985), Christou et al., Proc Natl. Acad. Sci. U.S.A. 84:3962 (1987). Direct uptake of DNA into protoplasts using CaCl.sub.2 precipitation, polyvinyl alcohol or poly-L-omithine has also been reported. Hain et al., Mol. Gen. Genet. 199:161 (1985) and Draper et al., Plant Cell Physiol. 23:451 (1982). Electroporation of protoplasts and whole cells and tissues have also been described. Saker, M.; Kuhne, T. Biologia Plantarum 40(4): 507-514 (1997/98), Donn et al., In Abstracts of VIIth International Congress on Plant Cell and Tissue Culture IAPTC, A2-38, p 53 (1990); D'Halluin et al., Plant Cell 4:1495-1505 (1992) and Spencer et al., Plant Mol. Biol. 24:51-61 (1994). See also Chupean et al., Biotechnology. 1989, 7: 5, 503-508.

Following transformation of celery target tissues, expression of the above-described selectable marker genes allows for preferential selection of transformed cells, tissues and/or plants, using regeneration and selection methods now well known in the art.

The foregoing methods for transformation would typically be used for producing a transgenic line. The transgenic line could then be crossed, with another (non-transformed or transformed) line, in order to produce a new transgenic celery line. Alternatively, a genetic trait that has been engineered into a particular celery cultivar using the foregoing transformation techniques could be moved into another line using traditional backcrossing techniques that are well known in the plant breeding arts. For example, a backcrossing approach could be used to move an engineered trait from a public, non-elite inbred line into an elite inbred line, or from an inbred line containing a foreign gene in its genome into an inbred line or lines which do not contain that gene. As used herein, “crossing” can refer to a simple X by Y cross, or the process of backcrossing, depending on the context.

Gene Conversions

When the term celery plant, cultivar or celery line is used in the context of the present invention, this also includes any gene conversions of that line. The term gene converted plant as used herein refers to those celery plants which are developed by a plant breeding technique called backcrossing wherein essentially all of the desired morphological and physiological characteristics of a cultivar are recovered in addition to the gene transferred into the line via the backcrossing technique. Backcrossing methods can be used with the present invention to improve or introduce a characteristic into the line. The term backcrossing as used herein refers to the repeated crossing of a hybrid progeny back to one of the parental celery plants for that line. The parental celery plant that contributes the gene for the desired characteristic is termed the nonrecurrent or donor parent. This terminology refers to the fact that the nonrecurrent parent is used one time in the backcross protocol and therefore does not recur. The parental celery plant to which the gene or genes from the nonrecurrent parent are transferred is known as the recurrent parent as it is used for several rounds in the backcrossing protocol (Poehlman & Sleper, 1994; Fehr, 1987). In a typical backcross protocol, the original cultivar of interest (recurrent parent) is crossed to a second line (nonrecurrent parent) that carries the single gene of interest to be transferred. The resulting progeny from this cross are then crossed again to the recurrent parent and the process is repeated until a celery plant is obtained wherein essentially all of the desired morphological and physiological characteristics of the recurrent parent are recovered in the converted plant, in addition to the single transferred gene from the nonrecurrent parent.

The selection of a suitable recurrent parent is an important step for a successful backcrossing procedure. The goal of a backcross protocol is to alter or substitute traits or characteristics in the original line. To accomplish this, a gene or genes of the recurrent cultivar are modified or substituted with the desired gene or genes from the nonrecurrent parent, while retaining essentially all of the rest of the desired genetic, and therefore the desired physiological and morphological, constitution of the original line. The choice of the particular nonrecurrent parent will depend on the purpose of the backcross. One of the major purposes is to add some commercially desirable, agronomically important trait or traits to the plant. The exact backcrossing protocol will depend on the characteristics or traits being altered to determine an appropriate testing protocol. Although backcrossing methods are simplified when the characteristic being transferred is a dominant allele, a recessive allele may also be transferred. In this instance it may be necessary to introduce a test of the progeny to determine if the desired characteristic has been successfully transferred.

Many gene traits have been identified that are not regularly selected for in the development of a new line but that can be improved by backcrossing techniques. Gene traits may or may not be transgenic, examples of these traits include but are not limited to, herbicide resistance, resistance for bacterial, fungal, or viral disease, insect resistance, enhanced nutritional quality, industrial usage, yield stability, yield enhancement, male sterility, modified fatty acid metabolism, and modified carbohydrate metabolism. These genes are generally inherited through the nucleus. Several of these gene traits are described in U.S. Pat. Nos. 5,777,196; 5,948,957 and 5,969,212, the disclosures of which are specifically hereby incorporated by reference.

Tissue Culture

Further reproduction of the variety can occur by tissue culture and regeneration. Tissue culture of various tissues of celery and regeneration of plants therefrom is well known and widely published. For example, reference may be had to Teng et al., HortScience. 1992, 27: 9, 1030-1032 Teng et al., HortScience. 1993, 28: 6, 669-1671, Zhang et al., Journal of Genetics and Breeding. 1992, 46: 3, 287-290, Webb et al., Plant Cell Tissue and Organ Culture. 1994, 38: 1, 77-79, Curtis et al., Journal of Experimental Botany. 1994, 45: 279, 1441-1449, Nagata et al., Journal for the American Society for Horticultural Science. 2000, 125: 6, 669-672, and Ibrahim et al., Plant Cell, Tissue and Organ Culture. (1992), 28(2): 139-145. It is clear from the literature that the state of the art is such that these methods of obtaining plants are routinely used and have a very high rate of success. Thus, another aspect of this invention is to provide cells which upon growth and differentiation produce celery plants having the physiological and morphological characteristics of cultivar 51-7 IPS 1.

As used herein, the term “tissue culture” indicates a composition comprising isolated cells of the same or a different type or a collection of such cells organized into parts of a plant. Exemplary types of tissue cultures are protoplasts, calli, meristematic cells, and plant cells that can generate tissue culture that are intact in plants or parts of plants, such as leaves, pollen, embryos, roots, root tips, anthers, pistils, flowers, seeds, petioles, suckers and the like. Means for preparing and maintaining plant tissue culture are well known in the art. By way of example, a tissue culture comprising organs has been used to produce regenerated plants. U.S. Pat. Nos. 5,959,185; 5,973,234 and 5,977,445 describe certain techniques, the disclosures of which are incorporated herein by reference.

Additional Breeding Methods

This invention also is directed to methods for producing a celery plant by crossing a first parent celery plant with a second parent celery plant wherein the first or second parent celery plant is a celery plant of cultivar 51-7 IPS 1. Further, both first and second parent celery plants can come from celery cultivar 51-7 IPS 1. Thus, any such methods using celery cultivar 51-7 IPS 1 are part of this invention: selfing, backcrosses, hybrid production, crosses to populations, and the like. All plants produced using celery cultivar 51-7 IPS 1 as at least one parent are within the scope of this invention, including those developed from cultivars derived from celery cultivar 51-7 IPS 1. Advantageously, this celery cultivar could be used in crosses with other, different, celery plants to produce the first generation (FI) celery hybrid seeds and plants with superior characteristics. The cultivar of the invention can also be used for transformation where exogenous genes are introduced and expressed by the cultivar of the invention. Genetic variants created either through traditional breeding methods using celery cultivar 51-7 IPS 1 or through transformation of cultivar 51-7 IPS 1 by any of a number of protocols known to those of skill in the art are intended to be within the scope of this invention.

The following describes breeding methods that may be used with celery cultivar 51-7 IPS 1 in the development of further celery plants. One such embodiment is a method for developing cultivar 51-7 IPS 1 progeny celery plants in a celery plant breeding program comprising: obtaining the celery plant, or a part thereof, of cultivar 51-7 IPS 1, utilizing said plant or plant part as a source of breeding material, and selecting a celery cultivar 51-7 IPS 1 progeny plant with molecular markers in common with cultivar 51-7 IPS 1 and/or with morphological and/or physiological characteristics selected from the characteristics listed in Table 1. Breeding steps that may be used in the celery plant breeding program include pedigree breeding, backcrossing, mutation breeding, and recurrent selection. In conjunction with these steps, techniques such as RFLP-enhanced selection, genetic marker enhanced selection (for example SSR markers) and the making of double haploids may be utilized.

Another method which may be used involves producing a population of celery cultivar 51-7 IPS 1-progeny celery plants, comprising crossing cultivar 51-7 IPS 1 with another celery plant, thereby producing a population of celery plants, which, on average, derive 50% of their alleles from celery cultivar 51-7 IPS 1. A plant of this population may be selected and repeatedly selfed or sibbed with a celery cultivar resulting from these successive filial generations. One embodiment of this invention is the celery cultivar produced by this method and that has obtained at least 50% of its alleles from celery cultivar 51-7 IPS 1.

One of ordinary skill in the art of plant breeding would know how to evaluate the traits of two plant varieties to determine if there is no significant difference between the two traits expressed by those varieties. For example, see Fehr and Walt, Principles of Cultivar Development, p 261-286 (1987). Thus the invention includes celery cultivar 51-7 IPS 1 progeny celery plants comprising a combination of at least two cultivar 51-7 IPS 1 traits selected from the group consisting of those listed in Table 1 or the cultivar 51-7 IPS 1 combination of traits listed above, so that said progeny celery plant is not significantly different for said traits than celery cultivar 51-7 IPS 1 as determined at the 5% significance level when grown in the same environmental conditions. Using techniques described herein, molecular markers may be used to identify said progeny plant as a celery cultivar 51-7 IPS 1 progeny plant. Mean trait values may be used to determine whether trait differences are significant, and preferably the traits are measured on plants grown under the same environmental conditions. Once such a variety is developed its value is substantial since it is important to advance the germplasm base as a whole in order to maintain or improve traits such as yield, disease resistance, pest resistance, and plant performance in extreme environmental conditions.

Progeny of celery cultivar 51-7 IPS 1 may also be characterized through their filial relationship with celery cultivar 51-7 IPS 1, as for example, being within a certain number of breeding crosses of celery cultivar 51-7 IPS 1. A breeding cross is a cross made to introduce new genetics into the progeny, and is distinguished from a cross, such as a self or a sib cross, made to select among existing genetic alleles. The lower the number of breeding crosses in the pedigree, the closer the relationship between celery cultivar 51-7 IPS 1 and its progeny. For example, progeny produced by the methods described herein may be within 1, 2, 3, 4 or 5 breeding crosses of celery cultivar 51-7 IPS 1.

The foregoing invention has been described in detail by way of illustration and example for purposes of clarity and understanding. However, it will be obvious that certain changes and modifications such as single gene modifications and mutations, somoclonal variants, variant individuals selected from large populations of the plants of the instant variety and the like may be practiced within the scope of the invention, as limited only by the scope of the appended claims.

Deposits

Applicant(s) have made a deposit of at least 2500 seeds of Celery Cultivar 51-7 IPS 1 with the American Type Culture Collection (ATCC), Manassas, Va. 20110 USA, ATCC Deposit No. PTA-125825. The seeds deposited with the ATCC on Mar. 20, 2019 were taken from the deposit maintained by ProScreen AG. Technology, Inc. 401 Victor Way, Suite 12 Salinas, CA 93907 since prior to the filing date of this application. Access to this deposit will be available during the pendency of the application to the Commissioner of Patents and Trademarks and persons determined by the Commissioner to be entitled thereto upon request. Upon issue of claims, the Applicant(s) will make available to the public, pursuant to 37 CFR 1.808, a deposit of at least 2500 seeds of cultivar 51-7 IPS 1 with the American type Culture Collection (ATCC), 10801 University Boulevard, Manassas, Va. 20110-2209. This deposit of the celery cultivar 51-7 IPS 1 will be maintained in the ATCC depository, which is a public depository, for a period of 30 years, or 5 years after the most recent request, or for the enforceable life of the patent, whichever is longer, and will be replaced if it becomes nonviable during that period. Additionally, Applicants have satisfied all the requirements of 37 C.F.R. §§ 1.801-1.809, including providing an indication of the viability of the sample. Applicants have no authority to waive any restrictions imposed by law on the transfer of biological material or its transportation in commerce. Applicants do not waive any infringement of their rights granted under this patent or under the Plant Variety Protection Act (7 USC 2321 et seq.). 

What is claimed is:
 1. A seed of celery cultivar 51-7 IPS 1, representative seed of said cultivar having been deposited under ATCC Accession No. PTA-125825.
 2. A celery plant, or a part thereof, produced by growing the seed of claim
 1. 3. A tissue culture comprising regenerable cells produced from the plant of claim
 2. 4. A protoplast produced from the tissue culture of claim
 3. 5. A protoplast produced from the plant of claim
 2. 6. The tissue culture of claim 3, wherein cells of the tissue culture are produced from a plant part selected from the group consisting of embryo, meristematic cell, leaf, cotyledon, hypocotyl, stem, root, root tip, pistil, anther, flower, seed, and pollen.
 7. A celery plant regenerated from the tissue culture of claim 3, said plant having all of the physiological and morphological characteristics of the celery plant of celery variety 51-7 IPS 1, representative seed of said variety having been deposited under ATCC Accession No. PTA-125825.
 8. A method for producing celery seed, said method comprising crossing the plant of claim 2 with itself or a different celery plant and harvesting the resulting seed.
 9. An F₁ celery seed produced by the method of claim
 8. 10. An F₁ celery plant produced by growing the seed of claim
 9. 11. A plant part of the celery plant of claim
 10. 12. A celery plant, or part thereof, having all the physiological and morphological characteristics of cultivar 51-7 IPS 1, representative seed of said cultivar having been deposited under ATCC Accession No. PTA-125825.
 13. A method of introducing a desired trait into celery cultivar 51-7 IPS 1, said method comprising: (a) crossing at least one 51-7 IPS 1 plant grown from 51-7 IPS 1 seed, representative seed of which has been deposited under ATCC Accession No. PTA-125825, with at least one plant of another celery cultivar that comprises a desired trait to produce at least one progeny plant; (b) selecting at least one progeny plant that has the desired trait to produce at least one selected progeny plant; (c) crossing at least one selected progeny plant with at least one 51-7 IPS 1 plant to produce at least one backcross progeny plant; (d) selecting for at least one backcross progeny plant that has the desired trait to produce at least one selected backcross progeny plant; and (e) repeating steps (c) and (d) three or more times in succession to produce at least one selected fourth or higher backcross progeny plant that comprise the desired trait.
 14. A celery plant produced by the method of claim 13, wherein the plant has the desired trait and all of the physiological and morphological characteristics of 51-7 IPS
 1. 15. A plant part of the plant of claim
 14. 16. The plant of claim 14, wherein the desired trait is selected from the group consisting of male sterility, herbicide resistance, insect resistance, disease resistance, enhanced nutritional quality, industrial usage, yield stability, yield enhancement, and a value added trait.
 17. The plant of claim 16, wherein the value-added trait is selected from the group consisting of increased iron content, decreased nitrate content, increased sweetness, modified fatty acid metabolism, and modified carbohydrate composition.
 18. A method for producing a celery plant of cultivar 51-7 IPS 1 further comprising a transgene, said method comprising transforming a plant of cultivar 51-7 IPS 1 with said transgene, wherein the transgene confers a trait into celery cultivar 51-7 IPS 1, wherein a representative sample of seed of variety 51-7 IPS 1 has been deposited under ATCC Accession No. PTA-125825.
 19. A celery plant, or part thereof, produced by the method of claim
 18. 20. The celery plant of claim 19, wherein the trait is selected from the group consisting of male sterility, herbicide resistance, insect resistance, disease resistance, enhanced nutritional quality, industrial usage, yield stability, yield enhancement, and a value added trait.
 21. The plant of claim 20, wherein the value-added trait is selected from the group consisting of increased iron content, decreased nitrate content, increased sweetness, modified fatty acid metabolism, and modified carbohydrate composition.
 22. A method for producing a seed of a celery plant from the plant of claim 2, the method comprising (a) crossing a plant of celery cultivar 51-7 IPS 1, wherein a representative sample of seed of said cultivar was deposited under ATCC Accession No. PTA-125825, with a second distinct celery plant; and (b) allowing seed to form; (c) growing a plant from the seed of step (b) to produce a plant obtained from celery cultivar 51-7 IPS 1; (d) selfing the plant of step (c) or crossing it to another celery plant to form additional celery seed derived from celery cultivar 51-7 IPS
 1. 